The present invention relates to a continuously adjustable seat back hinge mounting for a motor vehicle seat comprising a seat carrier and a seat back.
Usually, seat backs of motor vehicle seats are configured to be tilt-adjustable in order for the motor vehicle seat to be individually adaptable to the respective user. For this purpose, a seat back hinge mounting for pivoting the seat back is provided between the seat carrier and the seat back. Usually, such a motor vehicle seat also includes an underframe that is height-adjustable and comprises a lengthwise adjustment mechanism for example. The term seat carrier is meant to include any structure that is directly or indirectly adapted for use as a seat pan and that, as a rule, supports a seat cushion.
Motor vehicles are known in which the seat back is implemented to be tilt-adjustable some degrees, but there also exist seat backs that can be tilted all the way back to a sleeping position.
A major demand placed on the seat back hinge mounting is that it should allow for as easy and convenient an adjustment operation as possible on the one side while on the other side firmly connecting the seat back to the seat carrier for safety reasons. This is important because a seat back folding backward in the event of an accident may cause serious injuries to the user.
Seat back hinge mountings using an electric motor to allow for angular adjustment are known. Although such an electric motor allows for continuous adjustment of the seat back, it is cost prohibitive and depends for operation on an energy supply. Alternatively, mechanical seat back hinge mountings are known for detent adjustment. These mechanical seat back hinge mountings are lower in cost and do not need a source of energy; but, as a rule, they are not continuously adjustable.
The adjustment mechanisms allowing for continuous tilt-adjustment generally are of a very complicated construction and not very convenient to operate. The reason therefore often is that, since the tilt-adjustment is to be performed continuously, an adjustment wheel must be rotated many times in order to adjust the seat back. Usually, it is not possible to provide an absolutely zero clearance connection. Even if such a zero clearance connection is provided at the beginning of the useful life, clearance due to wear cannot be avoided after repeated used.
A generic seat back hinge mounting is shown in the document EP 0741056 A1 for example. FIG. 5 in particular illustrates a seat back hinge mounting that is purely mechanical and in which tilt adjustment is only possible in very small steps. The almost continuous adjustment is made possible through meshing teeth, one toothed element being fixed to the seat back and having teeth cooperating with an adjusting element fixed to the seat carrier. The disadvantage of this embodiment is that a zero clearance fit cannot be ensured in the long run. Also, genuine continuous adjustment is not possible.
It is the object of the present invention to provide a seat back hinge mounting for a motor vehicle seat that allows for continuous adjustment of the seat back tilt angle. It is intended that the seat back hinge mounting does not need any electric motor and is still easy and convenient to operate. Moreover, the seat back hinge mounting is intended to ensure zero clearance during the entire useful life thereof.